SHIRLEY – The Department of Correction is investigating the murder of a 72-year-old inmate who was found fatally beaten at the Souza Baranowski Correctional Center.

William Sires, who had been serving a life sentence, was murdered Tuesday afternoon in the state prison, according to a statement released Wednesday by Worcester County District Attorney Joseph D. Early Jr.

No arrests had been made in the murder by 5 p.m. Wednesday, said Timothy Connolly, a spokesman for Early.

"It's still under investigation," Connolly said.

Sires, who had been convicted of the 1973 murder of his mother in Pittsfield, was found badly beaten and near death in a cell at about 2 p.m. Tuesday, the statement said. He was pronounced dead in an ambulance en route to Leominster Hospital at 2:36 p.m.

A correction officer found Sires fatally wounded, and life-saving measures were performed, a Department of Correction statement said.